Non-typeable Haemophilus influenzae (NTHi) is an important and common respiratory pathogen that causes otitis media in infants and children. NTHi is, after Streptococcus pneumoniae, the most common cause of acute otitis media in children (J. Immunology 183: 2593-2601 (2009), Pediatrics 113:1451-1465 (2004)). It is an important cause of sinusitis in children and adults. (Current Infectious Disease Reports 11:177-182 (2009)). It has been associated with increased risk of exacerbations in chronic obstructive pulmonary disease (COPD) in adults. (Journal of Chronic Obstructive Pulmonary Disease 3:109-115 (2006)). In addition, non-typeable H. influenzae causes community-acquired pneumonia in adults and may cause pneumonia in children in developing countries. (Current Infectious Disease Reports 11:177-182 (2009)).
Streptococcus pneumoniae (S. pneumoniae), also known as the pneumococcus, is a Gram-positive bacterium. S. pneumoniae is a major public health problem all over the world and is responsible for considerable morbidity and mortality, especially among infants, the elderly and immunocompromised persons. S. pneumoniae causes a wide range of important human pathologies including community-acquired pneumonia, acute sinusitis, otitis media, meningitis, bacteremia, septicemia, osteomyelitis, septic arthritis, endocarditis, peritonitis, pericarditis, cellulitis, and brain abscess. S. pneumoniae is estimated to be the causal agent in 3,000 cases of meningitis, 50,000 cases of bacteremia, 500,000 cases of pneumonia, and 7,000,000 cases of otitis media annnually in the United States alone (Reichler, M. R. et al., 1992, J. Infect. Dis. 166: 1346; Stool, S. E. and Field, M. J., 1989 Pediatr. Infect. Dis J. 8: S11). Mortality rates due to pneumococcal disease are especially high in children younger than 5 years of age from both developed and developing countries. The elderly, the immunocompromised and patients with other underlying conditions (diabetes, asthma) are also particularly susceptible to disease.
The major clinical syndromes caused by S. pneumoniae are widely recognized and discussed in standard medical textbooks (Fedson D S, Muscher D M. In: Plotkin S A, Orenstein W A, editors. Vaccines. 4th edition. Philadelphia WB Saunders Co, 2004a: 529-588). For instance, Invasive pneumococcal disease (IPD) is defined as any infection in which S. pneumoniae is isolated from the blood or another normally sterile site (Musher D M. Streptococcus pneumoniae. In Mandell G L, Bennett J E, Dolin R (eds). Principles and Practice of Infectious diseases (5th ed). New York, Churchill Livingstone, 2001, p 2128-2147).
Chronic obstructive pulmonary disease is a chronic inflammatory disease of the lungs and a major cause of morbidity and mortality worldwide. Approximately one in 20 deaths in 2005 in the US had COPD as the underlying cause. (Drugs and Aging 26:985-999 (2009)). It is projected that in 2020 COPD will rise to the fifth leading cause of disability adjusted life years, chronic invalidating diseases, and to the third most important cause of mortality (Lancet 349:1498-1504 (1997)).
Thus a need for combination vaccines against Streptococcus pneumoniae and Haemophilus influenzae exists.
Protein E (PE) is an outer membrane lipoprotein with adhesive properties. It plays a role in the adhesion/invasion of non-typeable Haemophilus influenzae (NTHi) to epithelial cells. (J. Immunology 183: 2593-2601 (2009); The Journal of Infectious Diseases 199:522-531 (2009), Microbes and Infection 10:87-96 (2008)). It is highly conserved in both encapsulated Haemophilus influenzae and non-typeable H. influenzae and has a conserved epithelial binding domain. (The Journal of Infectious Diseases 201:414-419 (2010)). Thirteen different point mutations have been described in different Haemophilus species when compared with Haemophilus influenzae Rd as a reference strain. Its expression is observed on both logarithmic growing and stationary phase bacteria. (WO2007/084053).
Protein E is also involved in human complement resistance through binding vitronectin. (Immunology 183: 2593-2601 (2009)). PE, by the binding domain PKRYARSVRQ YKILNCANYH LTQVR (SEQ ID NO. 1, corresponding to amino acids 84-108 of SEQ ID NO. 4), binds vitronectin which is an important inhibitor of the terminal complement pathway. (J. Immunology 183:2593-2601 (2009)).
Pilin A (PilA) is likely the major pilin subunit of H. influenzae Type IV Pilus (Tfp) involved in twitching motility (Infection and Immunity, 73: 1635-1643 (2005)). NTHi PilA is a conserved adhesin expressed in vivo. It has been shown to be involved in NTHi adherence, colonization and biofilm formation. (Molecular Microbiology 65: 1288-1299 (2007)).
The inventors have found that PilA and PE may be beneficially present in an immunogenic composition for prevention of H. influenzae and furthermore that PilA and Protein E can be added to a composition comprising S. pneumoniae capsular saccharides in order to provide an immunogenic composition which can prevent H. influenzae and S. pneumoniae infection. The skilled person would be aware of the effect of carrier-induced epitopic suppression, and know that generally simultaneous exposure to multiple conjugate antigens can result in either enhanced or diminished immune responses (Plotkin et al, Vaccines fourth addition 2003).